Tipping actuator for a conveyor system

ABSTRACT

The invention relates to a tipping actuator for a conveyor system that comprises a plurality of article carriers moving on an endless conveyor in a conveying direction, each article carrier having a carrier frame for bearing an article, the carrier frame being pivotally mounted on the article carrier and operable to tip to enable discharge of the article borne on the carrier frame. The tipping actuator comprises a trigger member for contacting the article carriers to tip them and is configured such that, when in a non-contact position, the article carriers are able to at least partly tip towards the trigger member such that the contact portion of the trigger member is received by a portion of the article carrier. In another embodiment, a contact portion of the trigger is sloped with two different gradients. An electromagnet may be used to cause actuation of the trigger. The tipping actuator may be able to allow tipping in opposite directions of adjacent carriers, for example in some embodiments the trigger may be formed of upstream and downstream parts.

CLAIM OF PRIORITY

This application is a continuation of and claims priority to U.S.application Ser. No. 15/354,757 filed Nov. 17, 2016, entitled “TippingActuator For A Conveyor System”, which claims priority to U.S.application Ser. No. 14/426,528 filed Mar. 6, 2015, hich claims priorityto and is a 371 national stage application of PCT/NZ2013/000157, havingan international filing date of Sep. 4, 2013, which claims the benefitof priority to NZ 602280, filed Sep. 6, 2012, the entirety of hich isincorporated herein by reference.

FIELD OF THE DISCLOSURE

The invention relates to tipping actuators for conveyor systems andimprovements in such devices and their operability.

BACKGROUND TO THE DISCLOSURE

Conveyors are often used in grading machines to transport articlesthrough various measurement stages and to discharge the articles to sortthem dependent on the measurements. Such conveyors usually include anendless chain or belt on which are mounted a plurality of articlecarriers or cups. A discharge mechanism is used to unload objects atcertain points along the conveyor.

A common type of object that is graded and sorted by such a conveyorsystem is fruit. Fruit may be sorted based on criteria such as weight,shape, colour, ripeness and any other characteristic. Conveyor systemscomprise devices to measure these characteristics while the fruit isbeing transported. The position of each fruit and its respectivecharacteristics can be tracked so that a discharge mechanism causesitems of fruit to be unloaded from the conveyor and sent to the requireddestination, for example towards a chute or onto another conveyor.

The applicant's own U.S. Pat. No. 7,410,044 discloses an article carriersuitable to be mounted to a conveyor and used to sort fruit in a sortingassembly. A carrier frame is pivotable between a carriage position, inwhich fruit may be supported on the carrier frame, and a dischargeposition, in which fruit may fall off the carrier frame under gravityand thereby be discharged from the article carrier. The carrier framehas contact surfaces that may be contacted by an actuator when thecarrier frame is in the carriage position to cause the carrier frame totip into the discharge position and cause a fruit on the carrier frameto be unloaded. Advantageously the carrier frame can tip in bothsideways directions so that fruit can be discharged to either side.

A latch or locking member is engaged to the carrier frame and moveablebetween two positions in order to lock the carrier frame in position orto unlock the carrier frame and thus allow it to pivot on the articlecarrier.

In one version of an existing system, the actuator comprises a solenoidwhich, when activated, causes a pivotal trigger member to flick upwardsbefore falling under gravity. Activation is timed so that the triggermember impacts one of the contact surfaces of the locking member,causing it to move to the unlocked position and further to transfer theimpact to the carrier frame, causing the carrier frame to tip. Thismechanism requires a significant amount of energy to flick the triggerupwards, which is transmitted to the latch which engages the delatchingmechanism to thereupon transfer the force to the carrier frame. Theseseries of impacts makes the conveyor system very noisy, particularlywhere multiple tipping actuator mechanisms are operating simultaneously.Furthermore, the impact can have a different effect on fruit ofdifferent weights. Light fruit may be caused to jump off the articlecarrier rather than merely tipping off. This can damage fruit and alsomay cause the fruit to fall or bounce somewhere other than is intended.In contrast, the force of the impact may not be sufficient to tip thecarrier frame at all if it is carrying heavy fruit. Another drawback ofthe existing trigger mechanism is that there is a narrow window ofopportunity for the trigger to be activated and to impact the carrierframe correctly. This increases the complexity in the control system andmeans errors in fruit discharge can easily occur where the window ismissed.

The tipping trigger mechanism on MAF's Genesis conveyor system comprisesa generally triangular-shaped trigger plate that has a default positionlaterally outside the article carriers on the conveyor. The trigger canbe moved inwardly where the upper surface of the plate comes intocontact with an article carrier, causing it to tip away from thetrigger. The trigger is actuated by a solenoid and a spring biases thetrigger back to the default position once the solenoid is de-activated.When used with light fruit, the trigger may cause the article carrier totip violently, and therefore risks the fruit bouncing off erratically.Furthermore, the trigger is only able to accommodate the carrier tippingaway from the trigger, which reduces flexibility in the design of theconveyor system. Another problem with the MAF system is that the springmechanism to return the trigger to the default position can wear outover the course of repeated use.

The technology provides an improved tipping actuator for a conveyorsystem. Alternatively, the technology provides an improved conveyorsystem. Alternatively, the technology addresses one or more of thedisadvantages of prior tipping actuators and conveyor systems, such asthose described above. Alternatively, the technology provides the publicwith a useful choice.

SUMMARY OF THE DISCLOSURE

According to one embodiment, there is provided a tipping actuator for aconveyor system, the conveyor system comprising a plurality of articlecarriers moving on an endless conveyor in a conveying direction, eacharticle carrier having a carrier frame for bearing an article, thecarrier frame being pivotally mounted on the article carrier andoperable to tip to enable discharge of the article borne on the carrierframe, the tipping actuator comprising:

-   -   a trigger member having a contact portion for contacting the        article carriers; and    -   an actuation mechanism operable to move the trigger member        between a non-contact position, in which the contact portion is        positioned out of the path of the article carriers so as to        avoid contact therewith, and a contact position, in which the        contact portion is positioned in the path of the article        carriers to make contact therewith and effect tipping thereof        away from the trigger member,    -   wherein the trigger member is configured such that, when in the        non-contact position, the article carriers are able to at least        partly tip towards the trigger member such that the contact        portion of the trigger member is received by a portion of the        article carrier.

This allows for a compact conveyor system and means the trigger membermoves only a small distance between the contact and non-contactpositions.

In particular, the trigger member is configured such that, when in thenon-contact position, the article carriers are able to tip only partlytowards the trigger member prior to contacting the trigger member, thearticle carriers being able to tip fully once conveyed past the triggermember. A partial tipping of an article carrier followed by a fulltipping is a more gentle movement than a direct full tipping.

In one aspect, the actuation mechanism is operable to move at least partof the trigger member laterally between the non-contact and contactpositions. It will be understood that such a “lateral” movement of thetrigger member includes movements in which the trigger member rotatesaround a pivot but the rotation is sufficiently small that the upperedge of the trigger member moves generally horizontally. A lateralmovement is beneficial from the perspective of timing actuation of thetrigger. Other lateral movements incorporating a sliding or more complexmechanism may also be used.

In some embodiments of the disclosure, the trigger member comprises arecess in a downstream portion thereof in relation to the conveyingdirection. More preferably, the recess is configured such that triggermember avoids contacting the article carrier when the trigger member isin the contact position and one of the article carriers has moved justpast a downstream portion of the trigger member. In one embodiment, therecess may be shaped to compliment the shape of a part of the carrierframe. This feature allows tolerance of a greater error in the timing ofactuation of the trigger member into the contact position.

Throughout this description, the terms “upstream” and “downstream” willbe used to indicate relative positions of components relative to thedirection of travel of the conveyor, which is assumed to be moving inthe downstream direction.

In some exemplary embodiments, the trigger member is coupled to theactuation mechanism at an upstream portion thereof. For example, thetrigger member may be generally hook-shaped with the point of the hookextending in the downstream direction.

In some embodiments, the tipping actuator is operable to allow a firstarticle carrier on the endless conveyor to be or have been tippedtowards the trigger member and to effect tipping of a second consecutivearticle carrier on the endless conveyor away from the trigger member,the second consecutive article carrier being the article carrier on theendless conveyor immediately following the first article carrier.

In said embodiments, the trigger member preferably comprises upstreamand downstream trigger member parts, each trigger member part beingconfigured to effect tipping of the article carriers if positioned intheir path, wherein the upstream trigger member part is able to moveinto the contact position upon actuation of the actuation mechanism ifthe downstream trigger member part is constrained from moving into thecontact position. For example, the downstream trigger member may beconstrained by the article carrier when tipped towards the triggermember or otherwise constrained, for example, if the article carrier isin the carry position wherein the upstream trigger can advantageouslygain the position required to make an effective tip on the consecutivearticle carrier.

The tipping actuator may comprise a ramp located upstream of the triggermember and configured to move an article carrier from an articledischarge (tipped) position into an article carriage (non-tipped)position.

According to a another embodiment, there is provided a tipping actuatorfor a conveyor system, the conveyor system comprising a plurality ofarticle carriers moving on an endless conveyor in a conveying direction,each article carrier having a carrier frame for bearing an article, thecarrier frame being pivotally mounted on the article carrier andoperable to tip to enable discharge of the article borne on the carrierframe, the tipping actuator comprising:

-   -   trigger means having at least one contact portion for contacting        the article carriers; and    -   trigger actuation means operable to move the trigger means into        a contact position, in which the contact portion(s) is        positioned in the path of the article carriers to make contact        therewith and effect tipping thereof,    -   wherein the contact portion(s) comprises at least one contact        surface sloped towards the conveying direction and having at        least two gradients.

In one aspect, the trigger means comprises one sloped contact surface,the sloped contact surface having at least two gradients.

In another aspect, the sloped contact surface comprises at least a firstsection and a second section, the first section being located upstreamof the second section in relation to the conveying direction, the firstsection having a steeper gradient than the second section.

In some embodiments, at least part of the sloped contact surface of thecontact portion is curved. For example, the first and/or second sectionmay be curved.

In some embodiments, the first and/or second section may besubstantially straight. The sloped contact surface may comprise a curvedtransition section between the first and second sections.

In one aspect, the trigger means is configured such that, when a firstcontact surface contacts the article carrier, a locking member of thearticle carrier is lifted from a locked position, in which the carrierframe is unable to pivot on the article carrier, into an unlockedposition, in which the carrier frame is able to pivot on the articlecarrier. More preferably, the trigger means is configured such that,when a second contact surface contacts the article carrier, the carrierframe is tipped from the second article carriage position into anarticle discharge position.

In some embodiments, the tipping actuator comprises upstream anddownstream trigger member parts, each trigger member part beingconfigured to effect tipping of the article carriers if positioned intheir path, wherein the upstream trigger member part is able to moveinto the contact position upon actuation of the actuation mechanism ifthe downstream trigger member part is constrained from moving into thecontact position. For example, the downstream trigger member may beconstrained by the article carrier when tipped towards the triggermember.

In aspect, each trigger member part comprises at least one contactsurface for contacting the article carriers sloped towards the conveyingdirection and having at least two gradients.

The upstream and downstream trigger member parts may be independentlyoperable.

According to still another embodiment, there is provided a tippingactuator for a conveyor system, the conveyor system comprising aplurality of article carriers moving on an endless conveyor in aconveying direction, each article carrier having a carrier frame forbearing an article, the carrier frame being pivotally mounted on thearticle carrier and operable to tip to enable discharge of the articleborne on the carrier frame, the tipping actuator comprising:

-   -   a trigger member having a contact portion for contacting the        article carriers; and    -   an armature coupled to the trigger member, the armature        comprising or having mounted thereon an armature magnet; and    -   an electromagnet comprising a core;    -   wherein the electromagnet is switchable between on and off        states to cause the armature magnet to be attracted to and        repelled from the electromagnet, movement of the armature        causing the trigger member to move between a contact position,        in which the contact portion is positioned in the path of the        article carriers to make contact therewith and effect tipping        thereof, and a non-contact position, in which the contact        portion is positioned out of the path of the article carriers so        as to avoid contact therewith.

In one aspect, a portion of the trigger member comprises the armature.

In another aspect, the trigger member is pivotally mounted andconfigured to pivot on activation/deactivation of the electromagnet.

In some exemplary embodiments, the trigger member is pivotally mountedto pivot around a substantially horizontal axis.

In one embodiment, the trigger member comprises the armature at an enddistal to the contact portion, the trigger member being pivotallymounted at a point between the armature and contact portion.

In an aspect, when the electromagnet is in an off or de-activated state,the armature magnet is attracted to the core of the electromagnet. Morepreferably, when the armature magnet is attracted to the core of theelectromagnet, the trigger member is in the non-contact position.

The core of the electromagnet may be formed from a ferromagneticmaterial, such as iron or other ferrous material.

In one aspect, when the electromagnet is in an on or activated state,the armature magnet is repelled from the core of the electromagnet. Morepreferably, when the armature magnet is repelled from the core of theelectromagnet, the trigger member is in the contact position.

The tipping actuator may be configured such that the armature magnet ismounted on a surface of the armature facing towards the conveyor and theelectromagnet is positioned between the conveyor and the armature. Thisprovides for a compact arrangement and reduces the extent to which thetipping actuator extends outwards from the conveyor.

In some embodiments, the tipping actuator comprises upstream anddownstream trigger member parts, each trigger member part beingconfigured to effect tipping of the article carriers if positioned intheir path, wherein the upstream trigger member part is able to moveinto the contact position upon actuation of the actuation mechanism ifthe downstream trigger member part is constrained from moving into thecontact position. For example, the downstream trigger member may beconstrained by the article carrier when tipped towards the triggermember.

In said embodiments, the first electromagnet may be configured to causethe upstream trigger member part to move between the contact andnon-contact positions and the tipping actuator may comprise a furtherelectromagnet comprising a further core switchable between on and offstates to cause the downstream trigger member to move between thecontact and non-contact positions. The further electromagnet may beoperated in conjunction with, or independently from, the firstelectromagnet.

According to a still another embodiment, there is provided a tippingactuator for a conveyor system, the conveyor system comprising aplurality of article carriers moving on an endless conveyor in aconveying direction, each article carrier having a carrier frame forbearing an article, the carrier frame being pivotally mounted on thearticle carrier and operable to tip to enable discharge of the articleborne on the carrier frame, the tipping actuator comprising:

-   -   a trigger member having a contact portion for contacting the        article carriers; and    -   an actuation mechanism operable to move the trigger member        between a non-contact position, in which the contact portion is        positioned out of the path of the article carriers so as to        avoid contact therewith, and a contact position, in which the        contact portion is positioned in the path of the article        carriers to make contact therewith and effect tipping thereof        away from the trigger member,    -   wherein the tipping actuator is operable to allow a first        article carrier on the endless conveyor to be or have been        tipped towards the trigger member and to effect tipping of a        second article carrier on the endless conveyor away from the        trigger member, the second article carrier being the article        carrier on the endless conveyor immediately following the first        article carrier.

In one aspect, the trigger member comprises upstream and downstreamtrigger member parts, each trigger member part being configured toeffect tipping of the article carriers if positioned in their path,wherein the upstream trigger member part is able to move into thecontact position upon actuation of the actuation mechanism if thedownstream trigger member part is constrained from moving into thecontact position. For example, the downstream trigger member may beconstrained by the article carrier when tipped towards the triggermember.

In another aspect, each trigger member part comprises at least onecontact surface for contacting the article carriers sloped towards theconveying direction and having at least two gradients.

The upstream and downstream trigger member parts may be independentlyoperable.

It will be apparent that the tipping actuators of any of the first,second, third or fourth aspects of the invention may be provided incombination with the tipping actuators of any of the other aspects ofthe invention.

According to still another embodiment, there is provided a conveyorsystem comprising:

-   -   an endless conveyor configured to move in a conveying direction;    -   a plurality of article carriers mounted on the endless conveyor,        each article carrier having a carrier frame for bearing an        article, the carrier frame being pivotally mounted on the        article carrier and operable to tip to enable discharge of the        article borne on the carrier frame; and    -   at least one tipping actuator according to any one or more of        the first, second or third aspects of the invention mounted in        operable relation to the article carriers.

In one aspect, the conveyor system comprises at least two tippingactuators situated on opposing sides of the endless conveyor. Morepreferably, the two tipping actuators are positioned directly oppositeone another.

The conveyor system may further comprise at least one discharge stationat one or more locations along the endless conveyor for receivingarticles from the article carriers. More preferably, each dischargestation is positioned on the opposite side of the endless conveyor tothe tipping actuator operable to cause articles to be discharged intothe respective discharge station. More preferably still, at least twodischarge stations are positioned directly opposite one another.

Further aspects, which should be considered in all its novel aspects,will become apparent to those skilled in the art upon reading of thefollowing description which provides at least one example of a practicalapplication of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

One or more embodiments of the disclosure will be described below by wayof example only, and without intending to be limiting, with reference tothe following drawings, in which:

FIG. 1 is a side view illustration of a tipping actuator according to anembodiment of the invention;

FIG. 2 is a cross-sectional view illustration of the tipping actuatorshown in FIG. 1;

FIG. 3 is a cross-sectional view illustration of the tipping actuatorshown in FIG. 2 in an alternative configuration;

FIG. 4 is a rear view illustration of the tipping actuator shown inFIGS. 1 to 3 in use with an endless conveyor according to one embodimentof the invention;

FIG. 5 is a side view illustration of the conveyor system shown in FIG.4;

FIG. 6 is another side view illustration of the conveyor system shown inFIG. 4;

FIG. 7 is another side view illustration of the conveyor system shown inprevious figures;

FIG. 8 is another side view illustration of the conveyor system shown inthe other figures;

FIG. 9 is a front view illustration of the tipping actuator shown inFIG. 4 without an article being supported by the article carrier;

FIG. 10 is a side view illustration of a tipping actuator according toanother embodiment of the invention; and

FIG. 11 is an isometric view illustration of a conveyor system accordingto one embodiment of the invention.

DETAILED DESCRIPTION OF THE DISCLOSURE

Throughout the following description, unless specifically indicatedotherwise, like reference numerals refer to like components.

Tipping Actuator

FIG. 1 is a side view illustration of a tipping actuator 10 according toan embodiment of the invention. FIG. 2 is a cross-sectional viewillustration of the tipping actuator 10 shown in FIG. 1.

Tipping actuator 10 comprises a housing 11 a adapted to be mounted onthe side of an endless conveyor. In the embodiment shown, the tippingactuator 10 further comprises another housing 11 b adapted to be mountedon the opposite side of the conveyor to housing 11 a. Housings 11 a and11 b may be joined in some way, for example by a bracket 12. The twosides of tipping actuator 10 may be formed and may function in exactlythe same way so, for the purposes of the following description, only oneside of the tipping actuator will be described although the samedescription may also apply to the other side of the actuator. It isnoted that not all components of the left hand side of tipping actuator10 are illustrated in FIG. 2. In alternative embodiments of theinvention, the tipping actuator comprises only one of the sides of thetipping actuator shown in FIG. 2.

Between the two sides of tipping actuator 10 is formed a conveyorchannel 17 through which an endless conveyor is able to pass.

Tipping actuator 10 comprises a trigger member 13 pivotally mounted onthe housing 11 a and extending upwards therefrom. The upper portion ofthe trigger member 13 comprises a contact portion 14, which will bedescribed in detail later. The end of the trigger member 13 distal fromthe contact portion 14 comprises an armature 15, which comprises or hasmounted thereon a magnet 16. Trigger member 13 is able to pivot about apoint between the armature 15 and contact portion 14 by virtue of itsmounting in housing 11 a. The trigger member is thus able to movebetween a contact position, in which the contact portion 14 ispositioned inwardly as shown on the right hand side of FIG. 2, and anon-contact position, in which the contact portion is positionedoutwardly as shown on the left hand side of FIG. 2.

Inside housing 11 a there is an electromagnet having a magnetic (forexample a ferromagnetic or ferrous) core 18 with a solenoid 21 woundaround it. The electromagnet is able to be switched on and off by acontrol device to cause the fixed pole magnet 16 to be repelled from andattracted to the electromagnet, which moves the trigger member 13.

FIG. 3 is a cross-sectional view illustration of the tipping actuator 10shown in FIG. 2 but with the trigger member in the non-contact positionrather than the contact position (which is shown in FIG. 2).

The default position for the trigger member 13 is the non-contactposition as shown in FIG. 3, in which the magnet 16 is attracted to themagnetic core 18 of the electromagnet. Since magnet 16 is a permanentmagnet, no energy is required to maintain the trigger member in thenon-contact position.

To actuate the trigger member 13 into the contact position shown in FIG.2, the electromagnet is energised by a suitable control device. Thesolenoid winding 21 is configured to cause the electromagnet to repelmagnet 16, i.e. by causing the electromagnet to be formed with a pole atthe outwards facing end that is the same as the pole of the magnet 16 atthe inwards facing end. Repulsion between the electromagnet and magnet16 causes the armature 15 to move away from the electromagnet and thetrigger member to move into the contact position shown in FIG. 2.

This trigger actuation mechanism is highly robust and will only fail ifthe fixed polarity magnet loses its magnetism. The mechanism thereforehas a longer lifespan compared to actuation mechanisms using a spring orthe like to bias the trigger to its default position. A spring isvulnerable to fatigue and clogging with small components. In addition,the mechanism described herein has only a single bearing surface thatcontacts the article carriers, which reduces susceptibility to wearcompared to mechanisms with more bearing surfaces.

While any type of magnet or electromagnet may be used, in one exemplaryembodiment, the magnet 16 is a fixed polarity magnet. A fixed polaritymagnet may be used on account of its high remanence, or strength. Itwill be understood that the “magnetic core” of the electromagnet is acore formed from any material that is attracted to a magnet.

In the embodiment shown in FIGS. 2 and 3, one example of a triggermember actuation mechanism is illustrated but it will be evident thatother arrangements are also possible without departing from the scope ofthe invention. For example, while the trigger member 13 moves laterallybetween the contact and non-contact positions in the embodiment shown,the trigger member may alternatively be oriented differently and move inanother direction between the said positions. In another example, thepivot axis could be arranged vertically rather than horizontally.

In the embodiment of FIGS. 2 and 3, the trigger member 13 comprises thearmature 15 as an integral part thereof. It will be apparent that, inother embodiments, the armature may be mechanically coupled to thetrigger member in another appropriate manner.

Furthermore, in the embodiment of FIGS. 2 and 3, the electromagnet ispositioned between the conveyor channel 17 and the armature 15 with themagnet 16 mounted on a surface of the armature facing the conveyorchannel 17. This arrangement provides a compact lateral extent of thetipping actuator 10, meaning the width that the actuator protrudes outthe side of the conveyor is reduced. When conveyors are situatedadjacent to one another, minimal lateral extent means articles fromadjacent conveyors have more room to be discharged. However it will beapparent that, in other embodiments, other arrangements are possible.For example, the trigger member may be pivotally attached at a bottomend, with the magnet positioned above the pivot.

In some embodiments, the solenoid of the electromagnet may be surroundedby a metal casing, for example made from a sheet metal material. Whenmade from a ferromagnetic material, the metal casing may help to channelmagnetic flux produced by the electromagnet to increase the efficiencyof the solenoid. Insulating material may be disposed between thesolenoid and the metal casing to mitigate the possibility of sparking.

In some embodiments, the housing 11 a in which the actuation mechanismis housed may also be made from a similar sheet metal material tofurther increase the efficiency of the electromagnet. In fact, it hasbeen found that constructing the components of the actuation mechanismsuch that a magnetic circuit is formed, e.g. by making many componentsof the actuation mechanism from a ferrous material, increases thestrength of the electromagnet and therefore the acceleration of thetrigger. This reduces the time taken for the trigger to move into thepath of an article carrier, increasing the tolerance of the system totiming errors.

A ramp 19 may be comprised as part of the tipping actuator 10 or as aseparate component. The arrow on the ramp 19 shown in FIG. 1 indicatesthe conveying direction of the conveyor with which tipping actuator 10is configured to be used. As such, the ramp 19 is located upstream ofthe trigger member 13 in relation to the conveying direction. The ramp19 slopes upwards in the downstream direction and its function will bedescribed below. In some embodiments, the ramp may be integrally formedwith the housing 11 a.

Conveyor System

FIG. 4 is a rear view illustration of the tipping actuator 10 shown inFIGS. 1 to 3 in use with an endless conveyor 20 according to oneembodiment of the invention. FIG. 9 is a front view illustration of thesame tipping actuator and conveyor without an article being supported bythe article carrier. The tipping actuator 10 is mounted on the endlessconveyor 20 by means of a fixing 40, for example a screw, so that theconveyor passes through the conveyor channel 17 between the tippingactuator housings 11 a and 11 b. The endless conveyor 20 may be formedin any suitable manner, but in the embodiment shown comprises a seriesof chain links 21 joined end-to-end and operable to move around aconveyor extrusion 22.

Mounted on the endless conveyor 20 is a plurality of article carriers23, of which one is shown in FIG. 4. The article carriers 23 are mountedon the conveyor in any appropriate manner, for example by means of amounting clip 24. Each article carrier comprises a carrier frame 25,which in turn includes a support surface 26 and rollers 27 whichtogether define a cup for bearing an article 28.

The carrier frame 25 is mounted on the mounting clip 24 by means of apivotal connection 29. This allows the carrier frame 25 to move betweena carriage position, in which the support surface 26 is generallyhorizontal and article 28 is supported by the article carrier, and adischarge position, in which carrier frame 25 has tipped from thecarriage position so that the support surface 26 is not horizontal andthe article 28 discharges from the article carrier under gravity. Thecarrier frame is shown in the carriage position in FIG. 4. Pivotalconnection 29 may comprise a stop to limit the extent to which thecarrier frame 25 can pivot.

As described in the applicant's U.S. Pat. No. 7,410,044, the articlecarrier 23 or carrier frame 25 may comprise a latch or locking member 30that is moveable between two different positions. In one position of thelocking member, the carrier frame 25 is unable to pivot on the mountingclip 24 by virtue of an appropriate pivot locking mechanism. This isreferred to as the locked carriage configuration. In the second positionof the locking member, the carrier frame is free to pivot as has beendescribed and the locking mechanism is released. This is referred to asthe unlocked carriage configuration. In exemplary embodiments, thecarrier frame is in the locked carriage configuration when the lockingmember is in a low position on the mounting clip and can be raised intothe unlocked position by, for example, a portion of trigger member 13.

When the locking member is in the unlocked position, the carrier frameis able to be tipped by means of a tipping actuator such as thoseaccording to embodiments of the invention described herein. Some part ofthe locking member 30 or, in other embodiments some part of the carrierframe, presents a surface able to be contacted by the tipping actuatorto effect the tipping. In the embodiment shown in FIG. 4, locking member30 comprises lever arms 30 a and 30 b that extend sideways outwards fromthe article carrier and comprise a contact surface on their undersidesable to be contacted by the contact portions 14 of trigger members 13.The locking member 30 is contacted and pushed upwards against thecarrier frame 25 to cause the carrier frame to tip.

Operation of the Tipping Actuator

Operation of the tipping actuator 10 will be now be described inrelation to FIG. 4 and FIGS. 5 and 6, which are side view illustrationsof the conveyor system shown in FIG. 4. FIG. 5 illustrates the systemfrom one side and FIG. 6 is an illustration from the other side. In bothFIGS. 5 and 6, the passage of a single article carrier 23 is representedby a time progression of positions as it travels on the conveyor.

By default, the trigger members are in the non-contact position, forexample as is shown by trigger member 13 a in FIGS. 4 and 6. That is,the trigger member 13 a is positioned out of the path of the articlecarriers, and in particular out of the path of the lever arm of thelocking member 30, so contact is avoided as the article carrier 23 movespast the trigger member 13 a. For example, the arrangement of thetrigger actuation mechanism shown in FIG. 2 results in the triggermember 13 a being situated laterally outside the path of the articlecarriers.

Each trigger member is able to be selectively actuated into the contactposition in which it lies in the path of the next article carrier 23passing by on the conveyor by control of the associated electromagnet.Trigger member 13 b of FIGS. 4 and 5 is shown in the contact position.As can be seen most clearly in FIG. 5, the trigger member 13 b isdimensioned such that, when it is in the contact position, the articlecarrier is impinged by the trigger member and the contact surface on theunderside of the lever arm 30 b is contacted by the upper surface of thecontact portion of trigger member 13 a. This causes the locking member30 to be pushed upwards on the side nearest trigger member 13 b tounlock the carrier frame 25 and further to cause the carrier frame totip away from the trigger member 13 b and to discharge the article 28 onthe opposite side of the conveyor to the trigger member 13 b.

In contrast to the applicant's existing system described in theBackground to the Invention section of this document, which has atrigger member that flicks upwards to impact against the articlecarriers to effect their tipping, the present invention requires lessenergy to actuate the trigger member to cause tipping of the articlecarriers because the trigger member needs to move through a smallerdistance to be activated. This also makes the present inventionsignificantly less noisy when in operation than the existing system. Inaddition, the energy that causes the carrier to tip in the invention isgenerated by the conveyor itself—it is the motion of the conveyoragainst the trigger member that causes the tipping action. The dischargeof different weight articles can therefore be controlled by controllingthe speed of the conveyor without altering the actuation of the trigger.For example, to prevent light articles flying off the conveyor, theconveyor can be slowed slightly. The possibility of heavy articles beingfailed to be discharged by a trigger mechanism lacking sufficient energyis also avoided since the energy causing the discharge comes from themotion of the conveyor.

The locking member 30 comprises lever arms on both sides so that triggermembers can be positioned on both sides of the conveyor and the articlecarriers can be tipped in either direction to discharge articles oneither side of the conveyor. This may be useful when sorting or gradingproduce as more outlets can be situated in the same conveyor spacecompared to if the conveyor could only discharge articles on one side.It may be particularly useful to situate trigger members directlyopposite each other on the conveyor. In this configuration, the carrierframe 25 moves towards trigger member 13 a when it is tipped away fromtrigger member 13 b. This presents a risk that the trigger member on theside the carrier frame is tipped towards could prevent the carrier frametipping properly.

To address this, the tipping members, when in the non-contact position,are configured and positioned to avoid contact with the carrier frameswhen a carrier frame is tipped towards it. In one example, the tippingmembers are sufficiently far away from the conveyor in the non-contactposition that the carrier frames do not contact them. However, thisresults in a wide conveyor system, which impacts on the number ofconveyors able to be situated in a given area, and a trigger member thathas to move a large distance between the contact and non-contactpositions, which may require more energy and greater movement timecompared to a more compact conveyor. Therefore, in some embodiments ofthe invention, such as shown in FIG. 6, the trigger member 13 a isconfigured to be received by a portion of the carrier frame when thecarrier frame 25 is tipped towards the trigger member. That is, triggermember 13 a fits under a laterally extending arm 32 of the supportsurface 26 in the gap formed between the lateral extension 32 and thecarrier frame. As a result, trigger member 13 a does not prevent thecarrier frame from tipping. In this embodiment, the conveyor system iscompact in its width and, as shown in FIG. 4, the tipping actuator maynot extend outwards beyond the width of the carrier frame 25.

It can be seen in FIG. 6 that, shortly after the trigger member 13 b hascontacted the lever arm 30 b (as shown by the article carrier inposition X), the article carrier has partly tipped towards triggermember 13 a and, as described above, the configuration and position oftrigger member 13 a allows such partial tipping. In some embodiments,the trigger member 13 a in the non-contact position may be configured toprevent full tipping of the article carrier until the article carrierhas moved forwards on the conveyor to position Y. This may be desirablesince an initial partial tipping of the article carrier followed by afull tipping may make the tipping movement gentler than if the articlecarrier was allowed to immediately tip fully. This may ensure articlesare discharged from the conveyor without excessive violence, increasingthe chances of the article being discharged to the intended destination,for example an outlet chute.

The embodiments of tipping actuators according to the invention shown inthe Figures are tailored for use with one of the applicant's existingconveyor systems. There are significant advantages for those alreadyusing the applicant's conveyor systems to benefiting from the advantagesof the invention without the need to replace the conveyor systems.However the invention is not limited to use only with the applicant'sown systems, which are illustrated herein by way of example only. Itwill be apparent that tipping actuators within the scope of theinvention may be designed to operate with any appropriate conveyorsystem.

Profile of the Trigger

Referring again to FIG. 1, the contact portion 14 of the trigger member13 will now be discussed in more detail. The upper surface of thecontact portion 14 is the part of the trigger member 13 that contactsthe article carriers to effect their tipping. The contact surfacegenerally slopes upwards in the conveying direction so that the surfaceslopes towards the conveying direction. This slope allows the lever armof the article carrier to be contacted and pushed upwards by the triggermember.

The shape of the contact surface is configured to ease contact betweenthe trigger member 13 and the article carriers. Embodiments of theinvention comprise a contact surface having at least two gradients, forexample the contact surface may comprise two or more near-straightsections, as shown in the embodiment of FIG. 1, or the contact surfacemay be curved.

In the embodiment of FIG. 1, the contact surface comprises three surfacesections 101, 102 and 103. First surface section 101 is on the upstreamend of the contact surface of the trigger member 13 and is the lowest ofthe three sections. It also has the steepest gradient. This section isdesigned to make first contact with the locking member lever arm of anarticle carrier that impinges on the trigger member. In embodiments inwhich the article carrier comprises a carrier frame that can transitionbetween locked and unlocked carriage configurations by means of movingthe locking member vertically between locked and unlocked positions, thefirst surface section 101 is of sufficient height to lift the lockingmember from the locked to the unlocked position.

Second surface section 102 transitions the gradient of the contactsurface between the first surface section 101 and the third surfacesection 103, which is the highest of the three sections and has theshallowest gradient. The third surface section is at a sufficient heightto lift the locking member lever arm of the article carrier so that thearticle carrier tips over, as has been described above.

This stepped or gradual reduction in gradient of the contact surface ofthe trigger assists in controlling tipping of the article carrier.Rather than an impact that could cause articles on the carrier to getthrown off, the contact surface first unlocks the article carrier andthen causes a gradual tipping.

It will be evident that the invention includes embodiments in whichseparate triggers are provided, one which causes the unlocking of thearticle carrier and another that causes the tipping. However the use ofa single trigger to perform both actions may be more efficient and lesscomplex to construct.

Trigger Member Recess

As shown in FIG. 1, a recess 110 may be provided in an upstream portionof the trigger member 13. The trigger member 13 is generallyhook-shaped, with the point of the hook pointing downstream and therecess 110 formed by the hook.

One purpose of the recess 110 will now be described with reference toFIG. 7, which is another side view illustration of the conveyor systemshown in previous figures. Unlike FIGS. 5 and 6, FIG. 7 illustratesthree article carriers 23 a, 23 b and 23 c mounted one after another onthe conveyor system. Trigger member 13 is shown in the non-contactposition and allows the article carriers to pass by unimpinged.

Trigger member 13 is at the same height as the locking member lever arms30 of the article carriers 23 so that, when in the contact position thetrigger member contacts the lever arm of the next article carrier andcauses it to tip. This limits the window of opportunity available toactuate the trigger prior to the arrival of the article carrier thatneeds to be tipped. The trigger can only be actuated once the lever armof the previous article carrier, which may not need to be tipped, haspassed by.

In the embodiment shown in the Figures, the lever arm 30 comprises athin flange extending laterally out of the side of the carrier frame. Asshown in FIG. 7, when an article carrier is in the position of articlecarrier 23 c, it has sufficiently passed by the trigger member 13 forthe trigger member to close without contacting the lever arm 30. This ispossible because the recess 110 of the trigger member 13 has acomplimentary shape to the shape of lever arm 30. Therefore the triggermember can be actuated as soon as the article carrier has got to theposition of carrier 23 c. This increases the tolerance in the timing ofactuation compared to a similar system in which the recess 110 is notpresent and the trigger member extends downwards from the hooked end.Such a tolerance in timing of actuation reduces the accuracy andcomplexity required in the control system and also allows the operationof the conveyor system to tolerate variations in timing over the courseof time, for example the tendency for conveyors to stretch slightly withprolonged use.

Ramp

As mentioned above with reference to FIG. 1, the tipping actuator 10 maycomprise a ramp 19 located upstream from the trigger member 13. Thepurpose of ramp 19 will now be described with reference to FIG. 8, whichis a side view illustration of the conveyor system shown in the otherfigures with a single article carrier 23 shown in a number of differentpositions corresponding to its movement to the left in FIG. 8 over time.

In FIG. 8, article carrier 23 is initially in the discharge or tippedposition (shown on the right hand side of FIG. 8). The article carrier23 may have tipped accidently or have been tipped by an upstream tippingactuator. Ramp 19 rights the tipped article carrier. That is, it causesthe article carrier 23 to move from the article discharge or tippedposition into the article carriage or non-tipped position. Ramp 19 isconfigured to engage the lever arm of the locking member 30 and slopeupwards in the downstream direction to sufficient height for the carrierframe 25 to be stably brought into the carriage position. The shallowgradient of ramp 19 ensures the carrier frame is not righted with toomuch momentum which could cause the carrier frame to tip in the oppositedirection.

It will be appreciated that ramps may be positioned at any point alongthe conveyor system where the article carriers need to be righted andnot only immediately upstream of a tipping actuator.

Using ramps to right the article carriers helps to reduce wear andincrease the lifespan of a conveyor system. If many article carriers areleft tipped for a long stretch of a conveyor, their weight may affectthe balance of the conveyor and cause wear on one side.

Double Trigger Tipping Actuator

In a conveyor system, tipping one article carrier in one direction andthe immediately following article carrier in the opposite direction maybe problematic. The tipping actuator for the latter article carrier mayonly be activated once the first article carrier (that is tipped towardsthe tipping actuator) has passed. This is because the tipping actuatormay be impeded by a part of the article carrier. This therefore gives ashort period of time in which to activate the trigger and for thetrigger to move into position to contact the following article carrier.The available period of time in which to activate the trigger may beparticularly short where the speed of the conveyer is high or thespacing between article carriers is small.

In one embodiment of the invention, the positioning of the pivot of theactuator trigger is sufficiently high that the degree of movement of thetrigger member is small and it can be moved into position quickly.However this may result in a high degree of tolerance being neededduring manufacture and a smaller tolerance to wear, meaning that tippingmalfunctions are likely to happen sooner prior to parts needing to bereplaced.

FIG. 10 is a side view illustration of a tipping actuator 80 accordingto another embodiment of the invention. Tipping actuator 80 is similarin many respects to tipping actuator 10 shown in FIG. 1 and likereferences are used in relation to like parts. In the following, onlythose parts of tipping actuator 80 differing from tipping actuator 10will be described.

The trigger member 83 of tipping actuator 80 comprises an upstreamtrigger member part 81 and a downstream trigger member part 82. Each ofthe upstream and downstream trigger member parts 81 and 82 is configuredto cause tipping of the article carriers if positioned in their path, asdescribed above.

In operation, upstream trigger member part 81 is able to move intoposition to contact an article carrier even if downstream trigger memberpart 82 is constrained from moving. Such a situation is illustrated inFIG. 11, which is an isometric view illustration of a conveyor system 90according to one embodiment of the invention. In FIG. 11, the articlecarriers 91 are moving diagonally away and to the right. Article carrier91 a has been tipped towards tipping actuator 80 by another tippingactuator on the other side of the conveyor (not shown in FIG. 11) sothat article 92 a is falling off the conveyor towards the tippingactuator 80. However, article 92 b on carrier 91 b needs to be tipped inthe other direction, i.e. away from tipping actuator 80, and thereforetipping actuator 80 is actuated.

To ensure the trigger member of tipping actuator 80 is moved into thepath of carrier 91 b in time to tip it over, tipping actuator 80 hasbeen actuated while a part of carrier 91 a is still level with thetipping actuator 80. The presence of carrier 91 a when it is tippedtowards tipping actuator 80 prevents all of the trigger member frommoving into the path of the article carriers 91. However, at the pointshown in FIG. 11, upstream trigger member part 81 is free to move intothe path of the article carriers while downstream trigger member part 82is still constrained from moving by the presence of article carrier 91a. As a result, upstream trigger member 81 is able to move early toensure that article carrier 91 b is tipped in the opposite direction toarticle carrier 91 a.

In another embodiment of the invention, full actuation of the tippingactuator may be impeded by the roller part of the article carrier. Insuch an embodiment, the upstream trigger member may only be free to moveinto the path of the article carriers after the roller has movedsufficiently far downstream.

In a preferred embodiment of the invention, the upstream and downstreamtrigger member parts 81 and 82 are activated by separate electromagnetsbut the two electromagnets are activated together. In this embodiment,both trigger member parts are triggered together but they each only moveinto the contact position when they are not constrained from doing so.Therefore, in the situation described in relation to FIG. 11, theupstream trigger part 81 will move first, followed by the downstreamtrigger part 82.

In an alternative embodiment of the invention, the upstream anddownstream trigger member parts may be able to be activated by separateactuation mechanisms. This may allow only the upstream trigger member tobe triggered in a situation (such as the situation shown in FIG. 11)when constrained movement is likely, which may help to avoid damage tothe trigger member, depending on the actuation mechanism used. In astill further embodiment, the upstream and downstream trigger membersmay selectively be operable together or independently.

The profile shape of trigger member 83 in the embodiment of FIG. 10 issimilar to that of the trigger member 13 shown in FIG. 1 but theupstream and downstream trigger member parts 81 and 82 can be envisagedas being formed by splitting trigger member 13 vertically in two. Theshape of the interface of gap between the upstream and downstreamtrigger member parts in FIG. 10 is such that the downstream triggermember 82 comprises an upper contact surface that is sloped towards theconveying direction and has at least two gradients, as has beendescribed in more detail above. As a result, if the upstream triggerpart 81 fails to activate (for whatever reason), the downstream triggerpart 82 is shaped to tip the article carriers in a similar manner asdescribed above in relation to the single trigger member embodiments ofthe invention. In the embodiment shown in FIG. 10, the interface or gapbetween the top of the upstream and downstream trigger parts 81 and 82is at the point at which the upper contact surface of the trigger member83 changes.

Control System to Sort/Grade

It will be understood that the conveyor system described herein may beused to sort or grade articles of any type although particularapplication may be found in the field of fruit sorting and grading.

A sorting or grading apparatus may comprise an endless conveyor of thetype described above and a grading or sorting means such as aweighbridge, optical scanner or the like. A control system tracks themovement of the article carriers around the conveyor and activatestipping actuators to sort articles by certain characteristics, asmeasured by the grading or sorting means, by discharging articles of thesame characteristics into the same discharge station, which may comprisea further conveyor, chute or other article receiving means.

As has been described, the present invention advantageously allowstipping actuators to be positioned on directly opposing sides of theendless conveyor to make efficient use space while still benefiting fromother advantages of the invention described above or evident to theskilled addressee.

Unless the context clearly requires otherwise, throughout thedescription and the claims, the words “comprise”, “comprising”, and thelike, are to be construed in an inclusive sense as opposed to anexclusive or exhaustive sense, that is to say, in the sense of“including, but not limited to”.

The entire disclosures of all applications, patents and publicationscited above and below, if any, are herein incorporated by reference.

Reference to any prior art in this specification is not, and should notbe taken as, an acknowledgement or any form of suggestion that thatprior art forms part of the common general knowledge in the field ofendeavour in any country in the world.

The invention may also be said broadly to consist in the parts, elementsand features referred to or indicated in the specification of theapplication, individually or collectively, in any or all combinations oftwo or more of said parts, elements or features.

Where in the foregoing description reference has been made to integersor components having known equivalents thereof, those integers areherein incorporated as if individually set forth.

It should be noted that various changes and modifications to thepresently preferred embodiments described herein will be apparent tothose skilled in the art. Such changes and modifications may be madewithout departing from the spirit and scope of the invention and withoutdiminishing its attendant advantages. It is therefore intended that suchchanges and modifications be included within the present invention.

The invention claimed is:
 1. A tipping actuator for a conveyor system,the conveyor system comprising a plurality of article carriers moving onan endless conveyor in a conveying direction, each article carrierhaving a carrier frame for bearing an article, the carrier frame beingpivotally mounted on the article carrier and operable to tip to enabledischarge of the article borne on the carrier frame, the tippingactuator comprising: a trigger member having a contact portion forcontacting the article carriers; and an armature coupled to the triggermember, the armature comprising or having mounted thereon an armaturemagnet; and an electromagnet comprising a magnetic core; wherein theelectromagnet is switchable between on and off states to cause thearmature magnet to be attracted to and repelled from the electromagnet,movement of the armature causing the trigger member to move between acontact position, in which the contact portion is positioned in the pathof the article carriers to make contact therewith and effect tippingthereof, and a non-contact position, in which the contact portion ispositioned out of the path of the article carriers so as to avoidcontact therewith, wherein, when the electromagnet is in an off orde-activated state, the armature magnet is attracted to the magneticcore of the electromagnet and, when the electromagnet is in an on oractivated state, the armature magnet is repelled from the electromagnet.2. A tipping actuator as claimed in claim 1, wherein, when the armaturemagnet is attracted to the core of the electromagnet, the trigger memberis in the non-contact position and, when the armature magnet is repelledfrom the electromagnet, the trigger member is in the contact position.3. A tipping actuator as claimed in claim 1, wherein the tippingactuator is configured such that the armature magnet is mounted on asurface of the armature facing towards the conveyor and theelectromagnet is positioned between the conveyor and the armature.
 4. Atipping actuator as claimed in claim 1, wherein components of thetipping actuator form a magnetic circuit to increase the strength of theelectromagnet.
 5. A tipping actuator as claimed in claim 1, wherein thetipping actuator comprises upstream and downstream trigger member parts,each trigger member part being configured to effect tipping of thearticle carriers if positioned in their path, wherein the upstreamtrigger member part is able to move into the contact position even ifthe downstream trigger member part is constrained from moving into thecontact position.
 6. A tipping actuator as claimed in claim 5, whereinthe electromagnet is configured to cause the upstream trigger memberpart to move between the contact and non-contact positions and thetipping actuator comprises a further electromagnet switchable betweenfirst and second states to cause the downstream trigger member part tomove between the contact and non-contact positions.
 7. A tippingactuator as claimed in claim 1, wherein a portion of the trigger membercomprises the armature.
 8. A tipping actuator as claimed in claim 7,wherein the trigger member is pivotally mounted and configured to pivoton activation / deactivation of the electromagnet.
 9. A tipping actuatoras claimed in claim 8, wherein the trigger member is pivotally mountedto pivot around a substantially horizontal axis.
 10. A tipping actuatoras claimed in claim 8 wherein the trigger member comprises the armatureat an end distal to the contact portion, the trigger member beingpivotally mounted at a point between the armature and contact portion.11. A tipping actuator for a conveyor system, the conveyor systemcomprising a plurality of article carriers moving on an endless conveyorin a conveying direction, each article carrier having a carrier framefor bearing an article, the carrier frame being pivotally mounted on thearticle carrier and operable to tip to enable discharge of the articleborne on the carrier frame, the tipping actuator comprising: a triggermember having a contact portion for contacting the article carriers; anda pivotally mounted armature coupled to the trigger member, the armaturecomprising or having mounted thereon an armature magnet; and anelectromagnet; wherein the electromagnet is switchable between first andsecond states to cause the armature magnet to be attracted to andrepelled from the electromagnet and to thereby cause the armature topivot, pivoting of the armature causing the trigger member to movebetween a contact position, in which the contact portion is positionedin the path of the article carriers to make contact therewith and effecttipping thereof, and a non-contact position, in which the contactportion is positioned out of the path of the article carriers so as toavoid contact therewith.
 12. A tipping actuator as claimed in claim 11,wherein the tipping actuator is configured such that the armature magnetis mounted on a surface of the armature facing towards the conveyor andthe electromagnet is positioned between the conveyor and the armature.13. A tipping actuator as claimed in claim 11, wherein components of thetipping actuator form a magnetic circuit to increase the strength of theelectromagnet.
 14. A tipping actuator as claimed in claim 11, whereinthe electromagnet comprises a magnetic core and, when the electromagnetis in an off or de-activated state, the armature magnet is attracted tothe magnetic core of the electromagnet and, when the electromagnet is inan on or activated state, the armature magnet is repelled from theelectromagnet.
 15. A tipping actuator as claimed in claim 14, wherein,when the armature magnet is attracted to the magnetic core of theelectromagnet, the trigger member is in the non-contact position and,when the armature magnet is repelled from the electromagnet, the triggermember is in the contact position.
 16. A tipping actuator as claimed inclaim 11, wherein the tipping actuator comprises upstream and downstreamtrigger member parts, each trigger member part being configured toeffect tipping of the article carriers if positioned in their path,wherein the upstream trigger member part is able to move into thecontact position even if the downstream trigger member part isconstrained from moving into the contact position.
 17. A tippingactuator as claimed in claim 16, wherein the electromagnet is configuredto cause the upstream trigger member part to move between the contactand non-contact positions and the tipping actuator comprises a furtherelectromagnet switchable between first and second states to cause thedownstream trigger member part to move between the contact andnon-contact positions.
 18. A tipping actuator as claimed in claim 11,wherein a portion of the trigger member comprises the armature.
 19. Atipping actuator as claimed in claim 11, wherein the trigger member ispivotally mounted and configured to pivot on switching of theelectromagnet between the first and second states.
 20. A tippingactuator as claimed in claim 18, wherein the trigger member is pivotallymounted to pivot around a substantially horizontal axis.
 21. A tippingactuator as claimed in claim 18, wherein the trigger member comprisesthe armature at an end distal to the contact portion, the trigger memberbeing pivotally mounted at a point between the armature and contactportion.